Electric resistance



May 15, 1923., v1,455,462

C). WEEBER ELECTRIC RESISTANCE Filed April lO., 1918 Patented May 15, 1923. t

UNITED STATES PATENT OFFICE.

OTTO WEEBER, OF BERLIN, GERMANY, ASSIGNO'R, BY MESNE ASSIGNMENTS, T0 THE CHEMICAL FOUNDATION, INC., A CORPORATION OF DELAWARE.

ELECTRIC RESISTANCE.

Application filed April 10, 1918. Serial No. 227,817.

T0 all whom it may concern.'

Be it known that I, O'r'ro iVnnnnR, a German citizen, residing at Berlin, Germany, have invented certain new and useful lmprovements in Electric Resisfances (for which I filed application in Germany February 15, 1917), of which the following is ya specification.

My invention relates to electric resistanccs and more especially to rheostats and its particular object is a device of this kind of superior construction.

As is well known in rheostats having the resistance coil placed on prismatic carriers, two such carriers have been arranged parallel to each other, a sliding contact common to both coils being provided for connecting the coils either in parallel or in series. A similar arrangement has been used in ring resistances, the simultaneous shifting ofthe contact being effected byI a suitable intermediate gear. f

.All such arrangements, however, require considerable space and present many diflicultiesin mounting. vIn onder :to obviate these drawbacks, the rheostatacco'rding to the present invention contains ring-shaped resistances which are arranged co axially one within the other, spacing members bein inserted for Ventilating purposes, at suitable places on the carriers where no windings are provided. The carriers are connected by common carrying means with their axle bearing having the form of a support and carrying the sliding :contacts rotatably fixed on one side ofthe coils to a common arm. All parts are'thus rendered easily accessible and there is no danger 4of the resistances being unduly heated. Then the resistances are connected in series,I two brushes are required, and with the resistances placed in parallel three brushes, are required.4

In the drawings affixed to this specification and forming part thereof two modifications of `a rheostat according .to the present invention are illustrated, Figs. 1v and 2l being a vertical cross-sectionl and `a diagram, respectively, of L rheostat with the resistances connected in series, while Figs. 3 and 4 are similar views of a rheostat with the resistances connected in parallel.

Referring to Figs. 1 and .2 of the drawings, a and bA are two ring-shaped coil carriers arranged co-axially one Within the other, the portion of said carriers which is not covered by the coil being fixed by means of screws d and c to the support c, perforations being provided in these parts for introducing the wires. An intermediate piece f serves for securing the two carriers in the correct position relative to each other. The clip-shaped support c projects into the space enclosed by the inner carrier and serves for fixing the whole resistance to the plate h by means of screws g. The axle z' located in the support has an arm s fixed to its lower end in an easily removable Way, said arm carrying the laminated `contact brushes c and Z arranged one above the other and rigidly connected with each other by rivets and' screws, a stud t serving to fix the brushes to the arm s. The contact as a whole is fixed to the axle z' by aid of' a screw m so as to be easily removed therefrom: n is the connect.- ing terminal adapted to be adjusted relative to the axle to serve as\a contact for the outer end of the sliding contact, the binding screw n (Fig. l) being, to this end, inserted in the carrier with some room for free play and the terminal n being disposed as a flange provided on the carrier, so that by displacing the screw n and the iange a little the path of contact can easily be cleared.

In the modification illustrated in Figs. 3 and 4 besides the brushes ,7c and Z another laminated brush p is provided, said brush being short-circuited with the others and serving to conduct the current to a contact plate g arranged concentrically to the axle at about the level of the contact paths of the coil rings and from said plate to astationary terminal 7'.

I claim:

l. In a device of the class described, in combination, a plurality of concentric, spaced, ring-shaped members wound with resistance coils, said members being concentrically arranged-about a common axis, corresponding portionsof said members being free from wire, supporting means :for said members, an axle carrying a contact member for ycooperation with said coils, and means fol-'attaching said coils-to said support, said attaching means cooperating with those portions of the ring shaped members which are free from wire. Y

2,'In a device of the class described, in combination, a plurality 'of concentric,

spaced,ringshaped members Wound with resistance coils, said members being concentrically arranged about a common axis, corresponding portions of'said members being free from Wire, means for maintaining said ringshaped members and the coils wound thereon in spaced relation whereby the same may be readily cooled by ventilation, supporting means for said members,` an axle carrying a contact member for cooperation With said coils, and means for attachingsaid coils to said support, said attaching means cooperating with those portions ot' the ring-shaped members which are free from Wire.

3. In a device of the class described, in`

combination, a plurality of concentric,

spaced, ring-shaped members Wound with re-I sista-nce coils, said members being concen` trically arranged about a common axis, corresponding portions of said members being free from Wire, supporting means for said members, an axle carrying a contact member for cooperation with said coils, said contact member comprising a brush carrier disposed on said axle and a plurality of contact brushes removably carried by `said brush car-Y trically arranged about a common axis,cor responding portions of said members being free from wire, means for maintaining said ring-shaped members and the coils Wound thereon in spaced relation whereby the same may be readily cooled by ventilation, sup: porting means for said members, an axle carrying a contact member for cooperation with said coils, said Contact member comprisinv a brush carrier disposed on said axle ant a plurality of contact brushes removably carried by said brush carrier, and means for attachingsaid coils to said support, said at taching means cooperating` with those portions of the ring-shaped members which are free from Wire.

5. Ink a device of the class described in combination, two ring-shaped resistance coils disposed concentrically, one Within the space enclosed by the other, around a common axle, a brush carrier disposed on said axle, three contact brushes electrically connected With each other and removably arranged on said carrier, a contact plate disposed concentrically to said axle Within the space enclosed bv said coils, the coils and the plate being in sliding contact each with one of said brushes, an axle support and means common to both coils for ixing them to said support, said xing means being arranged on such parts of the said rings as are not covered by the Wire.

In testimony whereof I affix my signature.

` OTTO VVEE'BER. 

